Cancers
Characterization of CTC-HER2 Status in Patients with HER2-Low Invasive Breast Cancer
By Jennifer Hechao Chen, Salyna Meas, Roland L. Bassett and 3 others.
Abstract
Background
HER2 status is a dynamic process where one in ten patients with invasive breast cancer may undergo receptor conversion. We characterized HER2 status on circulating tumor cells (CTCs) in patients with HER2-low breast cancer.
Methods
Patients with HER2-low expression, defined as immunohistochemistry (IHC) score of 1+ or 2+ with negative HER2 fluorescent in situ hybridization, were enrolled from 2019 to 2023. All patients were treatment-naïve to HER2-targeted therapies. Blood draws were collected serially q3–6 months. CTCs were enumerated using CellSearch™ and HER2 expression on CTCs were detected using an anti-HER2 fluorescent antibody. Presence of ≥1 CTCs was considered positive. Wilcoxon rank-sum, Fisher’s exact test, and Kaplan–Meier method were used for statistical analysis.